Parking brake apparatus for vehicle

ABSTRACT

A parking brake apparatus for a vehicle includes a motor section receiving electric power from an outside, and generating power; a power transmission section rotated by driving the motor section, and including transmission worm gears; a pair of pressing units receiving power from the power transmission section and pressing a brake pad; a load transmission unit installed between the pair of pressing units, connected to each of the pair of pressing units, transmitting a pressing load of any one of the pair of pressing units to the other pressing unit, and made of a magnetic material; a magnet unit disposed to be spaced apart from the load transmission unit; and a hall sensor unit disposed between the load transmission unit and the magnet unit, and sensing a change in magnetic field according to rotation of the load transmission unit.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit of Korean PatentApplication No. 10-2019-0133820, filed on Oct. 25, 2019, which is herebyincorporated by reference for all purposes as if set forth herein.

BACKGROUND Field

Exemplary embodiments of the present disclosure relate to a parkingbrake apparatus for a vehicle, and more particularly, to a parking brakeapparatus for a vehicle capable of uniformly transmitting loads to abrake pad.

Discussion of the Background

In general, an actuator of an electronic parking brake for a vehicle isconstructed by a motor and a power transmission device for operatingfriction pads installed in a caliper of a disc brake apparatus whenparking.

When a driver pushes a parking brake switch, the rotational force of amotor of the actuator is transmitted to an input shaft of the caliperthrough the power transmission device such as a reduction gear. Throughthe rotation of the input shaft, a pressure connection sleeve is movedforward, and by the forward movement of the pressure connection sleeve,a piston which accommodates the pressure connection sleeve and a caliperhousing are moved toward each other, such that two friction pads mountedto the piston and the caliper housing are pressed against both surfacesof a disc to restrain the rotation of the disc.

In the case where a plurality of pistons are provided and receive adriving force from a single actuator, loads may be non-uniformlytransmitted to the plurality of pistons. In this case, uneven wear offriction pads may be caused, and the braking performance may bedegraded.

SUMMARY

Various embodiments are directed to a parking brake apparatus for avehicle capable of uniformly transmitting loads to a brake pad by a loadtransmission unit.

Also, various embodiments are directed to a parking brake apparatus fora vehicle capable of sensing, in real time, whether the loadtransmission unit normally operates.

In an embodiment, a parking brake apparatus for a vehicle may include: amotor section receiving electric power from an outside, and generatingpower; a power transmission section rotated by driving the motorsection, and including transmission worm gears; a pair of pressing unitsreceiving power from the power transmission section and pressing a brakepad; a load transmission unit installed between the pair of pressingunits, connected to each of the pair of pressing units, transmitting apressing load of any one of the pair of pressing units to the otherpressing unit, and made of a magnetic material; a magnet unit disposedto be spaced apart from the load transmission unit; and a hall sensorunit disposed between the load transmission unit and the magnet unit,and sensing a change in magnetic field according to rotation of the loadtransmission unit.

The load transmission unit may include a pair of ring gear sectionswhich are directly meshed with each other, each of the pair of ring gearsections may be rotatable by being meshed with a planetary gear section,at least any one of the pair of ring gear sections may be made of amagnetic material, the magnet unit may be disposed to face the ring gearsection which is made of the magnetic material, and the hall sensor unitmay sense a change in magnetic field according to rotation of the ringgear section.

The load transmission unit may include: a pair of ring gear sections;and at least one transmission gear section disposed between the pair ofring gear sections, and meshed with the ring gear sections, at least anyone of the pair of ring gear sections may be made of a magneticmaterial, the magnet unit may be disposed to face the ring gear sectionwhich is made of the magnetic material, and the hall sensor unit maysense a change in magnetic field according to rotation of the ring gearsection.

Each of the pair of ring gear sections may include: a ring gear innerpart formed with an internal gear portion on an inner circumferentialsurface thereof to be meshed with the planetary gear section; and a ringgear outer part coupled to an outer surface of the ring gear inner part,and formed with an external gear portion on an outer circumferentialsurface thereof to be meshed with the transmission gear section.

The ring gear inner part may project more toward the sun gear sectionthan the ring gear outer part, and may surround the sun gear section andthe planetary gear section.

The load transmission unit may include: a pair of ring gear sections;and at least one transmission gear section disposed between the pair ofring gear sections, and meshed with the ring gear sections, thetransmission gear section may be made of a magnetic material, the magnetunit may be disposed to face the transmission gear section which is madeof the magnetic material, and the hall sensor unit may sense a change inmagnetic field according to rotation of the transmission gear section.

Each of the pair of ring gear sections may include: a ring gear innerpart formed with an internal gear portion on an inner circumferentialsurface thereof to be meshed with the planetary gear section; and a ringgear outer part coupled to an outer surface of the ring gear inner part,and formed with an external gear portion on an outer circumferentialsurface thereof to be meshed with the transmission gear section.

The ring gear inner part may project more toward the sun gear sectionthan the ring gear outer part, and may surround the sun gear section andthe planetary gear section.

Each of the pair of pressing units may include: a sun gear sectionrotated by receiving power from the power transmission section; aplanetary gear section rotated by being meshed with the sun gearsection; a carrier section coupled to the planetary gear section; and apiston section connected to the carrier section, and pressing the brakepad by being moved toward the brake pad through receiving rotationalpower from the planetary gear section.

The power transmission section may further include a transmission wormwheel which is disposed at a middle portion of a transmission shaft, iscoupled to the motor section and receives power from the motor section;and the transmission worm gears may be disposed at both sides of thetransmission worm wheel, and may each transmit a rotation force of thetransmission worm wheel to the sun gear section.

In an embodiment, a parking brake apparatus for a vehicle may include: amotor section receiving electric power from an outside, and generatingpower; a power transmission section rotated by driving the motorsection, and including transmission worm gears; a pair of pressing unitsreceiving power from the power transmission section and pressing a brakepad; a load transmission unit installed between the pair of pressingunits, connected to each of the pair of pressing units, and transmittinga pressing load of any one of the pair of pressing units to the otherpressing unit; at least one magnet unit mounted to the load transmissionunit; and a hall sensor unit disposed to face the load transmissionunit, and sensing a change in magnetic field according to rotation ofthe load transmission unit.

The load transmission unit may include a pair of ring gear sectionswhich are directly meshed with each other, each of the pair of ring gearsections may be rotatable by being meshed with a planetary gear section,the magnet unit may be mounted to at least any one of the pair of ringgear sections, and the hall sensor unit may sense a change in magneticfield according to rotation of the ring gear section to which the magnetunit is mounted.

A plurality of magnet units may be provided, and may be disposed atregular intervals along a circumference of the ring gear section.

Each of the pair of ring gear sections may include: a ring gear innerpart formed with an internal gear portion on an inner circumferentialsurface thereof to be meshed with the planetary gear section; and a ringgear outer part coupled to an outer surface of the ring gear inner part,and formed with an external gear portion on an outer circumferentialsurface thereof to be meshed with the transmission gear section.

The ring gear inner part may project more toward the sun gear sectionthan the ring gear outer part, and may surround the sun gear section andthe planetary gear section.

The load transmission unit may include: a pair of ring gear sections;and at least one transmission gear section disposed between the pair ofring gear sections, and meshed with the ring gear sections, the magnetunit may be mounted to the transmission gear section, and the hallsensor unit may sense a change in magnetic field according to rotationof the transmission gear section to which the magnet unit is mounted.

A plurality of magnet units may be provided, and may be disposed atregular intervals along a circumference of the transmission gearsection.

Each of the pair of ring gear sections may include: a ring gear innerpart formed with an internal gear portion on an inner circumferentialsurface thereof to be meshed with the planetary gear section; and a ringgear outer part coupled to an outer surface of the ring gear inner part,and formed with an external gear portion on an outer circumferentialsurface thereof to be meshed with the transmission gear section.

The ring gear inner part may project more toward the sun gear sectionthan the ring gear outer part, and may surround the sun gear section andthe planetary gear section.

Each of the pair of pressing units may include: a sun gear sectionrotated by receiving power from the power transmission section; aplanetary gear section rotated by being meshed with the sun gearsection; a carrier section coupled to the planetary gear section; and apiston section connected to the carrier section, and pressing the brakepad by being moved toward the brake pad through receiving rotationalpower from the planetary gear section.

In the parking brake apparatus for a vehicle according to the presentdisclosure, when a pressing load is concentrated on any one of aplurality of pressing units, a load transmission unit may transmit thepressing load to the remaining pressing unit, so that the pressing unitsmay press a brake pad with uniform loads.

Also, according to the present disclosure, since it is possible tosense, in real time, whether the load transmission unit normallyoperates, it is possible to immediately take countermeasures in case ofabnormal operation of the load transmission unit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a parking brake apparatus fora vehicle in accordance with an embodiment of the present disclosure.

FIG. 2 is a partial perspective view illustrating the parking brakeapparatus for a vehicle in accordance with the embodiment of the presentdisclosure.

FIG. 3 is a partial exploded view illustrating the parking brakeapparatus for a vehicle in accordance with the embodiment of the presentdisclosure.

FIG. 4 is a front view illustrating the parking brake apparatus for avehicle in accordance with the embodiment of the present disclosure.

FIGS. 5 to 7 are state views illustrating driving states of the parkingbrake apparatus for a vehicle in accordance with the embodiment of thepresent disclosure.

FIG. 8 is a view illustrating a state in which a hall sensor unit isdisposed at a side of a ring gear section in the parking brake apparatusfor a vehicle in accordance with the embodiment of the presentdisclosure.

FIG. 9 is a view illustrating a state in which the hall sensor unit isdisposed at a side of a transmission gear section in the parking brakeapparatus for a vehicle in accordance with the embodiment of the presentdisclosure.

FIG. 10 is a view illustrating a state in which a magnet unit is mountedto the ring gear section in the parking brake apparatus for a vehicle inaccordance with the embodiment of the present disclosure.

FIG. 11 is a view illustrating a state in which a plurality of magnetunits are mounted to the ring gear section in the parking brakeapparatus for a vehicle in accordance with the embodiment of the presentdisclosure.

FIG. 12 is a view illustrating a state in which the magnet unit ismounted to the transmission gear section in the parking brake apparatusfor a vehicle in accordance with the embodiment of the presentdisclosure.

FIG. 13 is a view illustrating a state in which the plurality of magnetunits are mounted to the transmission gear section in the parking brakeapparatus for a vehicle in accordance with the embodiment of the presentdisclosure.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Hereinafter, a parking brake apparatus for a vehicle will be describedbelow with reference to the accompanying drawings through variousexamples of embodiments. It should be noted that the drawings are not toprecise scale and may be exaggerated in thickness of lines or sizes ofcomponents for descriptive convenience and clarity only.

Furthermore, the terms used herein are defined by taking functions ofthe invention into account and can be changed according to the intentionof users or operators or the practice. Therefore, definition of theterms should be made according to the overall disclosures set forthherein.

FIG. 1 is a perspective view illustrating a parking brake apparatus fora vehicle in accordance with an embodiment of the present disclosure.FIG. 2 is a partial perspective view illustrating the parking brakeapparatus for a vehicle in accordance with the embodiment of the presentdisclosure. FIG. 3 is a partial exploded view illustrating the parkingbrake apparatus for a vehicle in accordance with the embodiment of thepresent disclosure. FIG. 4 is a front view illustrating the parkingbrake apparatus for a vehicle in accordance with the embodiment of thepresent disclosure. FIGS. 5 to 7 are state views illustrating drivingstates of the parking brake apparatus for a vehicle in accordance withthe embodiment of the present disclosure.

FIG. 8 is a view illustrating a state in which a hall sensor unit isdisposed at a side of a ring gear section in the parking brake apparatusfor a vehicle in accordance with the embodiment of the presentdisclosure, FIG. 9 is a view illustrating a state in which the hallsensor unit is disposed at a side of a transmission gear section in theparking brake apparatus for a vehicle in accordance with the embodimentof the present disclosure, FIG. 10 is a view illustrating a state inwhich a magnet unit is mounted to the ring gear section in the parkingbrake apparatus for a vehicle in accordance with the embodiment of thepresent disclosure, FIG. 11 is a view illustrating a state in which aplurality of magnet units are mounted to the ring gear section in theparking brake apparatus for a vehicle in accordance with the embodimentof the present disclosure, FIG. 12 is a view illustrating a state inwhich the magnet unit is mounted to the transmission gear section in theparking brake apparatus for a vehicle in accordance with the embodimentof the present disclosure, and FIG. 13 is a view illustrating a state inwhich the plurality of magnet units are mounted to the transmission gearsection in the parking brake apparatus for a vehicle in accordance withthe embodiment of the present disclosure.

Referring to FIGS. 1 to 5 , a parking brake apparatus 1 for a vehicle inaccordance with the embodiment of the present disclosure includes adriving unit 50, pressing units 100 and 200, and a load transmissionunit 300.

The driving unit 50 includes a motor section 60 which receives electricpower from the outside and generates power. The motor section 60includes a motor body 61 which generates power and a driving gear 62which is rotated by the motor body 61.

In the present embodiment, the driving gear 62 is formed in the shape ofa worm gear, but the shape thereof may be replaced with other gearshapes or the likes as long as the driving gear 62 can transmit power tothe pressing units 100 and 200 or a power transmission section 70.

The driving unit 50 further includes a power transmission section 70.That is to say, the motor section 60 of the driving unit 50 mayindirectly transmit generated power to the pressing units 100 and 200through the power transmission section 70.

The power transmission section 70 includes a transmission shaft 71, atransmission worm wheel 72, and transmission worm gears 73. Thetransmission worm wheel 72 is meshed with the driving gear 62 andreceives power from the driving gear 62.

The transmission worm wheel 72 is disposed at the middle portion of thetransmission shaft 71, and the transmission worm gears 73 are disposedat both sides of the transmission worm wheel 72, respectively.Therefore, if the transmission worm wheel 72 is rotated by the drivinggear 62, each of the transmission worm gears 73 at both ends of thetransmission shaft 71, which are connected to the transmission wormwheel 72, is rotated in an interlocked manner.

As such, according to the present embodiment, even though onetransmission worm wheel 71 is rotated using one motor section 60, thetwo transmission worm gears 73 which are connected to the transmissionworm wheel 72 may be simultaneously rotated, which makes it possible tosimultaneously provide power to the pair of pressing units 100 and 200.

In other words, the power transmission section 70 has a structure inwhich one transmission worm wheel 72 is installed at the middle portionof the transmission shaft 71 and the pair of transmission worm gears 73are connected to the transmission worm wheel 72 and are installed atboth sides of the transmission worm wheel 72, respectively, and thus,can simultaneously transmit the same force to each of the pair ofpressing units 100 and 200.

In addition, since power can be transmitted by including only thetransmission worm wheel 72 and the transmission worm gears 73, thestructure of the power transmission section 70 may be simplified,whereby the assemblability and operational reliability may be improvedand an installation space may be reduced.

In addition, by adjusting the spacing between the transmission wormgears 73 disposed at both sides of the transmission worm wheel 72, thespacing between the pressing units 100 and 200 may be adjusted.

Referring to FIGS. 1 to 3 , the parking brake apparatus 1 for a vehiclein accordance with the present embodiment includes a mounting case 400and a mounting cover (not illustrated).

The driving unit 50, the pressing units 100 and 200 and the loadtransmission unit 300 are disposed in the mounting case 400. Themounting cover is detachably coupled to the mounting case 400, andcloses one side opening of the mounting case 400 to prevent foreignmatters from entering the inside of the mounting case 400.

The pressing units 100 and 200 in accordance with the embodiment of thepresent disclosure are installed in a caliper housing 10, receive powerfrom the driving unit 50, and press a brake pad 20 which is brought intofrictional contact with a disc (not illustrated).

A plurality of pressing units 100 and 200 are provided. The plurality ofpressing units 100 and 200 are disposed side by side. The pressing units100 and 200 are symmetrically installed at left and right sides (in FIG.4 ) with respect to the center portion of the brake pad 20.

The pressing units 100 and 200 receive power from the driving unit 50,and press the brake pad 20 with the same pressing loads. The brake pad20 is moved toward the disc by such pressing forces, and a braking forceis generated due to the friction between the brake pad 20 and the disc.

The pressing units 100 and 200 in accordance with the embodiment of thepresent disclosure include the sun gear sections 110 and 210, theconnection gear sections 120 and 220, the planetary gear sections 130and 230, carrier sections 150 and 250, and the piston sections 170 and270.

Meanwhile, in the illustration of FIGS. 4 to 7 , connection gear bodies121 and 221 of the connection gear sections 120 and 220 are omitted forthe sake of convenience in explanation.

The connection gear sections 120 and 220 include the connection gearbodies 121 and 221, connection worm wheels 122 and 222, and connectinginsertion parts 123 and 223.

The connection gear sections 120 and 220 include the connection wormwheels 122 and 222 formed on the outer circumferential surfaces thereofto be meshed with the driving unit 50, specifically, the transmissionworm gears 73 of the power transmission section 70, respectively.

Due to this fact, the power generated in the motor section 60 istransmitted to the connection worm wheels 122 and 222 through the powertransmission section 70. That is to say, the power of the driving unit50 is transmitted to the connection gear sections 120 and 220 androtates the connection gear sections 120 and 220. The connection wormwheels 122 and 222 are formed in the shapes of worm wheels.

The connecting insertion parts 123 and 223 are formed in spaces insidethe connection worm wheels 122 and 222. In other words, the connectionworm wheels 122 and 222 are formed on the outsides of walls formed onthe outer circumferential surfaces of the connection gear bodies 121 and221, and the connecting insertion parts 123 and 223 are formed in thespaces inside the walls on which the connection worm wheels 122 and 222are formed.

Ring gear sections 310, specifically, ring gear inner parts 311, areinserted into the connecting insertion parts 123 and 223. The connectinginsertion parts 123 and 223 are formed in the shapes of grooves.

The sun gear sections 110 and 210 are rotated by receiving power fromthe driving unit 50. According to the present embodiment, the sun gearsections 110 and 210 are coupled to the connection gear sections 120 and220. The sun gear sections 110 and 210 may be rotated through theconnection gear sections 120 and 220 which are dynamically connected tothe driving unit 50.

The sun gear sections 110 and 210 include sun gears 111 and 211 and sungear connection bodies 112 and 212.

The sun gear connection bodies 112 and 212 are coupled to the connectiongear bodies 121 and 221. The sun gears 111 and 211 are formed at thecenter portions of the sun gear connection bodies 112 and 212, and areformed in the shapes of gears on the outer circumferential surfacesthereof to be meshed with the planetary gear sections 130 and 230.

The rotation centers of the sun gear sections 110 and 210 are concentricwith the rotation centers of the connection gear sections 120 and 220.Therefore, if power is transmitted to the connection gear sections 120and 220 by the power transmission section 70, the connection gearsections 120 and 220 and the sun gear sections 110 and 210 are rotatedabout the same rotation axes.

The sun gear sections 110 and 210 are disposed inside the innercircumferential surfaces of the connection gear sections 120 and 220 onwhich the connecting insertion parts 123 and 223 are formed.

The sun gear sections 110 and 210 may be integrally formed with theconnection gear sections 120 and 220. Alternatively, the sun gearsections 110 and 210 may be formed as separate bodies from theconnection gear sections 120 and 220, and may be integrated with theconnection gear sections 120 and 220 through coupling.

As the sun gear sections 110 and 210 are integrally formed with theconnection gear sections 120 and 220 or are integrated with theconnection gear sections 120 and 220, if the connection gear sections120 and 220 which are driven by receiving power from the powertransmission section 70 are rotated, the sun gear sections 110 and 210are also rotated together.

The sun gears 111 and 211 are disposed inside the planetary gearsections 130 and 230, respectively, each of which is provided with aplurality of gears. The planetary gear sections 130 and 230 rotate andrevolve while being meshed with the sun gears 111 and 211.

The planetary gear sections 130 and 230 include a plurality of planetarygears 131 and 231. The present embodiment illustrates that the numbersof the planetary gears 131 and 231 each are exemplified as four.However, it is to be noted that the present embodiment is not limitedthereto, and thus, the numbers of the planetary gears 131 and 231 mayeach be three or less or five or more.

The plurality of planetary gears 131 and 231 are disposed at equalangles about the rotation centers of the sun gears 111 and 211. Theplurality of planetary gears 131 and 231 are meshed with the sun gears111 and 211, and rotate and/or revolve when the sun gears 111 and 211are rotated.

The planetary gear sections 130 and 230 are coupled to the carriersections 150 and 250. In the case where the plurality of planetary gears131 and 231 revolve around the sun gears 111 and 211, the carriersections 150 and 250 are also rotated in a clockwise or counterclockwisedirection (in FIG. 4 ).

As the carrier sections 150 and 250 are rotated, the piston sections 170and 270 are moved toward the brake pad 20 and press the brake pad 20.

The carrier sections 150 and 250 include carrier bodies 151 and 251,carrier rotation shafts 152 and 252, and carrier connection parts 153and 253.

The carrier rotation shafts 152 and 252 are formed on the carrier bodies151 and 251 to project toward the planetary gear sections 130 and 230.

The carrier rotation shafts 152 and 252 are provided in plural numbersthat are the same as the numbers of the planetary gears 131 and 231 ofthe planetary gear sections 130 and 230, and are coupled through theplanetary gears 131 and 231 of the planetary gear sections 130 and 230.Due to this fact, the planetary gears 131 and 231 of the planetary gearsections 130 and 230 may perform rotating motion while being rotated onthe carrier rotation shafts 152 and 252.

The carrier connection parts 153 and 253 are formed on the innercircumferential surfaces of the carrier bodies 151 and 251, and areconnected to piston connection parts 173 and 273 of the piston sections170 and 270.

In the present embodiment, the carrier connection parts 153 and 253 havegrooves, and the piston connection parts 173 and 273 have protrusionswhich are inserted into the grooves of the carrier connection parts 153and 253.

Alternatively, the piston connection parts 173 and 273 may have grooves,and the carrier connection parts 153 and 253 may have protrusions whichare inserted into the grooves of the piston connection parts 173 and273.

The carrier connection parts 153 and 253 and the piston connection parts173 and 273 may be spline-coupled to each other. Of course, the carriersections 150 and 250 and the piston sections 170 and 270 may be coupledin other ways, for example, screw coupling or the like, in addition tothe spline coupling.

The piston sections 170 and 270 are connected with the carrier sections150 and 250. The piston sections 170 and 270 are rotated together as thecarrier sections 150 and 250 are rotated.

The piston sections 170 and 270 include piston bodies 171 and 271,piston shafts 172 and 272, and the piston connection parts 173 and 273.

The piston bodies 171 and 271 are formed to be internally hollow, andare disposed to be capable of being brought into contact with the brakepad 20 by the movement thereof. The piston bodies 171 and 271 may beformed in cylindrical shapes.

The piston bodies 171 and 271 are coupled with the piston shafts 172 and272, and the piston connection parts 173 and 273 are formed at ends ofthe piston shafts 172 and 272, that is, ends of the piston shafts 172and 272 which face the carrier sections 150 and 250.

When the carrier sections 150 and 250 are rotated, the piston connectionparts 173 and 273 which are spline-coupled to the carrier connectionparts 153 and 253 are rotated, and thereby, the rotational motion of thecarrier sections 150 and 250 is converted into the linear motion of thepiston sections 170 and 270.

Due to the linear movement of the piston sections 170 and 270, thepiston sections 170 and 270 are moved toward the brake pad 20.Therefore, as the piston sections 170 and 270 are brought into contactwith the brake pad 20 and press the brake pad 20, a braking force isgenerated due to the friction between the brake pad 20 and the disc.

The load transmission unit 300 is connected to each of the pair ofpressing units 100 and 200, and transmits a pressing load of any one ofthe pressing units 100 and 200 to the other of the pressing units 100and 200.

The load transmission unit 300 in accordance with the embodiment of thepresent disclosure includes the pair of ring gear sections 310. The loadtransmission unit 300 may further include one or more transmission gearsections 320.

The pair of ring gear sections 310 are meshed with the planetary gearsections 130 and 230, respectively, to be able to be rotated thereby.

The pair of ring gear sections 310 may be directly meshed with eachother. In other words, the pair of ring gear sections 310 may bedirectly connected with each other without disposing the transmissiongear sections 320 therebetween. In this case, the spacing between thepair of ring gear sections 310 illustrated in FIG. 4 , that is, thespacing between the connection gear sections 120 and 220 at one side andthe other side, is further reduced, and thus, in conformity with this,the spacing between the transmission worm gears 73 at the one side andthe other side, which are meshed with the connection gear sections 120and 220, may be further reduced.

Alternatively, the pair of ring gear sections 310 may be indirectlymeshed by the medium of the one or more transmission gear sections 320.Namely, the transmission gear sections 320 may be disposed between thepair of ring gear sections 310 and meshed with the ring gear sections310.

Referring to FIGS. 3 to 7 , the respective ring gear sections 310 may beinstalled between the planetary gears 131 and 231 and the connectionworm wheels 122 and 222.

Each ring gear section 310 includes the ring gear inner part 311 and aring gear outer part 315.

The ring gear inner parts 311 are disposed outside the planetary gearsections 130 and 230, and internal gear portions 312 may be formed onthe inner circumferential surfaces of the ring gear inner parts 311 tobe meshed with the planetary gear sections 130 and 230.

The internal gear portion 312 of the ring gear inner part 311 which isinstalled at one side (the left side in FIG. 5 ) is meshed with theplanetary gear section 130 to be rotated in the clockwise orcounterclockwise direction (in FIG. 5 ), and transmits power to the ringgear section 310, specifically, the ring gear outer part 315, which isdisposed at the other side (the right side in FIG. 5 ), through thetransmission gear sections 320.

The ring gear outer part 315 is coupled to the outer surface of the ringgear inner part 311, and an external gear portion 316 is formed on theouter circumferential surface of the ring gear outer part 315 to bemeshed with the transmission gear section 320. The ring gear outer part315 may be integrally formed with the ring gear inner part 311.

As the internal gear portion 312 of the ring gear inner part 311 whichis installed at the one side (the left side in FIG. 5 ) is rotated whilebeing meshed with the planetary gear section 130, the ring gear outerpart 315 which is integrally formed with the ring gear inner part 311 isalso rotated in the same direction.

Therefore, the rotational force of the ring gear outer part 315 at theone side is transmitted to the ring gear section 310, specifically, thering gear outer part 315, which is disposed at the other side (the rightside in FIG. 5 ), through the transmission gear sections 320.

The transmission gear sections 320 are rotated by being meshed with theexternal gear portions 316 which are formed on the ring gear sections310, specifically, the ring gear outer parts 315, and transmit therotational power of the ring gear section 310 disposed at the one sideto the ring gear section 310 disposed at the other side.

The rotational power transmitted to the ring gear section 310 at theother side is transmitted to the carrier section 250 which is coupled tothe planetary gears 231, via the ring gear inner part 311 and theplanetary gears 231. As the planetary gears 231 rotate and revolve onthe outer circumferential surface of the sun gear 211, the carriersection 250 which is coupled to the planetary gears 231 is rotated, andthus, the piston section 270 is moved toward the brake pad 20.

In the case where pressing loads for pressing the brake pad 20 arenon-uniformly applied to the pair of pressing units 100 and 200,specifically, the pair of piston sections 170 and 270, the loadtransmission unit 300 may transmit a pressing load of the piston section170 at the one side to the piston section 270 at the other side suchthat the pair of piston sections 170 and 270 may be brought into contactwith the brake pad 20 with uniform pressing loads.

Of course, conversely, a pressing load of the piston section 270 at theother side may be transmitted to the piston section 170 at the one side.

Referring to FIGS. 4 to 7 , in the present embodiment, the transmissiongear sections 320 are formed in the shapes of spur gears, and arerotated by being meshed with the external gear portions 316 formed onthe outer circumferential surfaces of the ring gear outer parts 315.

However, in addition to the shapes of spur gears, the shapes of thetransmission gear sections 320 may be replaced with various shapes suchas the shapes of bevel gears and the shapes of helical gears whose gearteeth are formed to be inclined at a predetermined angle with respect tothe rotation axes of the transmission gear sections 320.

Moreover, while it is illustrated that the transmission gear sections320 have the shapes of gears, it is to be noted that the disclosure isnot limited thereto, and various modifications are possible like aconfiguration in which the transmission gear sections 320 are connectedin the shapes of belts to the pair of ring gear sections 310 andtransmit power of the pressing unit 100 at the one side to the pressingunit 200 at the other side.

The number of the ring gear sections 310 of the load transmission unit300 may be changed. Therefore, the number of the ring gear sections 310is not limited to two as in the present embodiment, and may be variouslychanged to one or three or more depending on a distance between the pairof pressing units 100 and 200.

The operation principle of the parking brake apparatus 1 for a vehicleconstructed as mentioned above will be described below.

In the parking brake apparatus 1 for a vehicle in accordance with theembodiment of the present disclosure, the plurality of pressing units100 and 200 press the brake pad 20 to move the brake pad 20 toward thedisc, and a braking force is generated due to the contact frictionbetween the brake pad 20 and the disc.

In the embodiment of the present disclosure, two pressing units 100 and200 are provided. However, it is to be noted that the present disclosureis not limited thereto, and various modifications such as three or morepressing units are possible.

The pressing units 100 and 200 receive power from the driving unit 50,and are linearly reciprocated relative to the brake pad 20.

In detail, when power is generated in the motor section 60 by receivingelectric power from the outside, the power transmission section 70 whichis connected with the motor section 60 is rotated by receiving powerfrom the motor section 60. The power transmission section 70simultaneously transmits rotational power to the pair of pressing units100 and 200.

By driving the motor section 60, the transmission worm wheel 72 isrotated, and accordingly, as the respective transmission worm gears 73are rotated, the connection gear sections 120 and 220 which are meshedwith the transmission worm gears 73 are rotated.

According to the rotation of the connection gear sections 120 and 220,the sun gear sections 110 and 210 are also rotated in an interlockedmanner, and the planetary gears 131 and 231 which are meshed with thesun gears 111 and 211 perform rotating motion and at the same timeperform revolving motion around the sun gears 111 and 211.

As the planetary gears 131 and 231 perform the revolving motion, thecarrier sections 150 and 250 which are coupled to the planetary gears131 and 231 are rotated in the clockwise or counterclockwise direction.As the carrier sections 150 and 250 are rotated, the piston sections 170and 270 which are coupled to the carrier sections 150 and 250 are movedtoward the brake pad 20 and press the brake pad 20 by being brought intocontact with the brake pad 20.

Due to various factors, the power provided from the driving unit 50 maybe transmitted more to any one of the pair of pressing units 100 and200.

As illustrated in FIG. 6 , when driving the parking brake apparatus 1for a vehicle, in the case where power is transmitted more to thepressing unit 100 disposed at the one side (the left side in FIG. 6 )than the pressing unit 200 disposed at the other side (the right side inFIG. 6 ), the piston section 170 at the one side may be brought intocontact with the brake pad 20 earlier than the piston section 270 at theother side.

If the piston section 170 at the one side is in a state in which it isalready brought into contact with the brake pad 20 and the pistonsection 270 at the other side is in a state in which it is not yetbrought into contact with the brake pad 20, the planetary gear section130 of the pressing unit 100 at the one side performs only rotatingmotion. That is to say, the planetary gear section 130 does not performrevolving motion.

Since the power generated by the operation of the driving unit 50 iscontinuously transmitted to the sun gear 111, the sun gear 111 iscontinuously rotated. At this time, since the piston section 170 is inthe state in which it is already brought into contact with the brake pad20, the plurality of planetary gears 131 which are meshed with the sungear 111 do not perform revolving operation but perform only rotatingmotion.

Since the pressing unit 100, specifically, the piston section 170, whichis disposed at the left side in FIG. 6 can no longer be moved toward thebrake pad 20, due to a reaction force to this, the planetary gears 131perform only rotating motion, and the ring gear inner part 311 which isformed with the internal gear portion 312 to be meshed with theplanetary gears 131 is rotated in the clockwise or counterclockwisedirection.

The reaction force, which is generated in the pressing unit 100 at theone side (the left side in FIG. 6 ) through the ring gear outer part 315which is integrally coupled with the ring gear inner part 311, istransmitted to the pressing unit 200 at the other side (the right sidein FIG. 6 ) through the transmission gear sections 320.

In detail, the power provided to the pressing unit 100 at the one sideis transmitted to the piston section 270 at the other side through theexternal gear portion 316 at the other side, the internal gear portion312 of the ring gear inner part 311, the planetary gear section 230 andthe carrier section 250 coupled with the planetary gear section 230.

Accordingly, the power provided from the driving unit 50 is provided tothe piston section 270 at the other side which is not yet brought intocontact with the brake pad 20, and the linear movement of the pistonsection 170 at the one side which is already brought into contact withthe brake pad 20 is stopped until the piston section 270 at the otherside is brought into contact with the brake pad 20.

Thereafter, when both the piston sections 170 and 270 at the one sideand the other side are brought into contact with the brake pad 20, thepower of the driving unit 50 is provided to the respective pistonsections 170 and 270 at the one side and the other side, and the pistonsections 170 and 270 at the one side and the other side simultaneouslypress the brake pad 20 with uniform loads.

Referring to FIGS. 4 to 7 , in the case where a pressing load isconcentrated on the pressing unit 100 at the one side between the pairof pressing units 100 and 200, the load transmission unit 300 inaccordance with the embodiment of the present disclosure may transmitthe pressing load to the pressing unit 200 at the other side such thatthe pair of pressing units 100 and 200 may press the brake pad 20 towardthe disc with uniform pressing loads.

Likewise, in the case where a pressing load is more concentrated on thepressing unit 200 at the other side between the pair of pressing units100 and 200, the load transmission unit 300 may transmit the pressingload to the pressing unit 100 at the one side such that the pair ofpressing units 100 and 200 may press the brake pad 20 toward the discwith uniform pressing loads.

Referring to FIG. 3 , the ring gear inner parts 311 may project moretoward the sun gear sections 110 and 210 (the left side in FIG. 3 ) thanthe ring gear outer parts 315, and may be inserted into the connectinginsertion parts 123 and 223 of the connection gear sections 120 and 220.

Due to this fact, it is possible to prevent the ring gear sections 310from being released from the connection gear sections 120 and 220 or thesun gear sections 110 and 220 when receiving rotational power from thedriving unit 50.

As the carrier sections 150 and 250 are spline-coupled to the pistonsections 170 and 270, the rotational power of the carrier sections 150and 250 may be transmitted to the piston sections 170 and 270,specifically, the piston connection parts 173 and 273.

The piston connection parts 173 and 273 are coupled to the piston shafts172 and 272 which are coupled to the piston bodies 171 and 271, and, bythe rotational power received through the carrier sections 150 and 250,cause the piston bodies 171 and 271 to be linearly moved toward thebrake pad 20.

Referring to FIGS. 8 and 9 , the parking brake apparatus 1 for a vehiclein accordance with the embodiment of the present disclosure may furtherinclude a hall sensor unit 510 and a magnet unit 520.

In the present embodiment, the load transmission unit 300 may be made ofa magnetic material. For example, the load transmission unit 300 may bemade of a ferromagnetic material.

The magnet unit 520 is disposed to be spaced apart from the loadtransmission unit 300. In detail, the magnet unit 520 is disposed at aposition where the load transmission unit 300 may be magnetized in amagnetic field.

The hall sensor unit 510 is disposed between the load transmission unit300 and the magnet unit 520, and senses a change in magnetic fieldaccording to the rotation of the load transmission unit 300.

When the load transmission unit 300 is rotated, a magnetic field ischanged. The hall sensor unit 510 determines whether the loadtransmission unit 300 normally operates, by measuring the number ofrevolutions, the rotation speed, etc. of the load transmission unit 300based on a change in magnetic field. In the case where it is determinedthat the load transmission unit 300 operates abnormally, the hall sensorunit 510 alarms the outside through an alarm unit (not illustrated) sothat a driver or the like may recognize the abnormal operatingsituation.

Referring to FIG. 8 , at least any one of the pair of ring gear sections310 is made of a magnetic material.

The magnet unit 520 is disposed to face the ring gear section 310 whichis made of the magnetic material, and the hall sensor unit 510 senses achange in magnetic field according to the rotation of the ring gearsection 310 which is made of the magnetic material.

The hall sensor unit 510 determines whether the ring gear section 310normally operates, by measuring the number of revolutions, the rotationspeed, etc. of the ring gear section 310 based on a change in magneticfield according to the rotation of the ring gear section 310. In thecase where it is determined that the ring gear section 310, that is, theload transmission unit 300, operates abnormally, the hall sensor unit510 alarms the outside through the alarm unit so that the driver or thelike may recognize the abnormal operating situation.

Referring to FIG. 9 , at least any one of the pair of transmission gearsections 320 is made of a magnetic material.

The magnet unit 520 is disposed to face the transmission gear section320 which is made of the magnetic material, and the hall sensor unit 510senses a change in magnetic field according to the rotation of thetransmission gear section 320 which is made of the magnetic material.

The hall sensor unit 510 determines whether the transmission gearsection 320 normally operates, by measuring the number of revolutions,the rotation speed, etc. of the transmission gear section 320 based on achange in magnetic field according to the rotation of the transmissiongear section 320. In the case where it is determined that thetransmission gear section 320, that is, the load transmission unit 300,operates abnormally, the hall sensor unit 510 alarms the outside throughthe alarm unit so that the driver or the like may recognize the abnormaloperating situation.

Referring to FIGS. 10 to 13 , the parking brake apparatus 1 for avehicle in accordance with the embodiment of the present disclosure mayfurther include a hall sensor unit 510 and a magnet unit 520.

In the present embodiment, the magnet unit 520 may be mounted to theload transmission unit 300.

The hall sensor unit 510 is disposed to face the load transmission unit300, and senses a change in magnetic field according to the rotation ofthe load transmission unit 300.

When the load transmission unit 300 is rotated, a magnetic field ischanged. The hall sensor unit 510 determines whether the loadtransmission unit 300 normally operates, by measuring the number ofrevolutions, the rotation speed, etc. of the load transmission unit 300based on a change in magnetic field. In the case where it is determinedthat the load transmission unit 300 operates abnormally, the hall sensorunit 510 alarms the outside through an alarm unit (not illustrated) sothat a driver or the like may recognize the abnormal operatingsituation.

Referring to FIG. 10 , the magnet unit 520 is mounted to at least anyone of the pair of ring gear sections 310.

The hall sensor unit 510 senses a change in magnetic field according tothe rotation of the ring gear section 310 to which the magnet unit 520is mounted.

The hall sensor unit 510 determines whether the ring gear section 310normally operates, by measuring the number of revolutions, the rotationspeed, etc. of the ring gear section 310 based on a change in magneticfield according to the rotation of the ring gear section 310. In thecase where it is determined that the ring gear section 310, that is, theload transmission unit 300, operates abnormally, the hall sensor unit510 alarms the outside through the alarm unit so that the driver or thelike may recognize the abnormal operating situation.

Referring to FIG. 11 , a plurality of magnet units 520 are disposed atregular intervals along the circumference of at least any one of thepair of ring gear sections 310.

As the plurality of magnet units 520 are disposed in the ring gearsection 310, the accuracy of detecting a change in magnetic field in thehall sensor unit 510 may be improved.

Referring to FIG. 12 , the magnet unit 520 is mounted to at least anyone of the pair of transmission gear sections 320.

The hall sensor unit 510 senses a change in magnetic field according tothe rotation of the transmission gear section 320 to which the magnetunit 520 is mounted.

The hall sensor unit 510 determines whether the transmission gearsection 320 normally operates, by measuring the number of revolutions,the rotation speed, etc. of the transmission gear section 320 based on achange in magnetic field according to the rotation of the transmissiongear section 320. In the case where it is determined that thetransmission gear section 320, that is, the load transmission unit 300,operates abnormally, the hall sensor unit 510 alarms the outside throughthe alarm unit so that the driver or the like may recognize the abnormaloperating situation.

Referring to FIG. 13 , a plurality of magnet units 520 are disposed atregular intervals along the circumference of at least any one of thepair of transmission gear sections 320.

As the plurality of magnet units 520 are disposed in the transmissiongear section 320, the accuracy of detecting a change in magnetic fieldin the hall sensor unit 510 may be improved.

Although the disclosure has been disclosed with reference to theembodiments illustrated in the drawings, the embodiments are only forillustrative purposes, and those skilled in the art will appreciate thatvarious modifications and other equivalent embodiments are possible,without departing from the scope and spirit of the disclosure as definedin the accompanying claims. Thus, the true technical scope of thedisclosure should be defined by the following claims.

What is claimed is:
 1. A parking brake apparatus for a vehicle,comprising: a motor section receiving electric power from an outside,and generating power; a power transmission section rotated by drivingthe motor section, and including transmission worm gears; a pair ofpressing units receiving power from the power transmission section andpressing a brake pad; a load transmission unit installed between thepair of pressing units, connected to each of the pair of pressing units,transmitting a pressing load of any one of the pair of pressing units tothe other pressing unit, and made of a magnetic material; a magnet unitdisposed to be spaced apart from the load transmission unit andconfigured to generate a magnetic field in the area of the loadtransmission unit; and a hall sensor unit disposed between the loadtransmission unit and the magnet unit, and sensing a change in themagnetic field according to rotation of the load transmission unit,wherein the load transmission unit includes gears for transmitting thepressing load, the magnet unit is disposed to face the gears of the loadtransmission unit, and the hall sensor unit is configured to determineabnormal operation of the load transmission unit based on a change inthe magnetic field corresponding to a change in rotation of the gears ofthe load transmission unit.
 2. The parking brake apparatus of claim 1,wherein the gears of the load transmission unit comprise a pair of ringgear sections which are directly meshed with each other, wherein each ofthe pair of ring gear sections is rotatable by being meshed with aplanetary gear section, wherein at least any one of the pair of ringgear sections is made of a magnetic material, and wherein the magnetunit is disposed to face the ring gear section which is made of themagnetic material, and the hall sensor unit senses a change in magneticfield according to rotation of the ring gear section.
 3. The parkingbrake apparatus of claim 1, wherein the gears of the load transmissionunit comprise: a pair of ring gear sections; and at least onetransmission gear section disposed between the pair of ring gearsections, and meshed with the ring gear sections, wherein at least anyone of the pair of ring gear sections is made of a magnetic material,and wherein the magnet unit is disposed to face the ring gear sectionwhich is made of the magnetic material, and the hall sensor unit sensesa change in magnetic field according to rotation of the ring gearsection.
 4. The parking brake apparatus of claim 3, wherein each of thepair of ring gear sections comprises: a ring gear inner part formed withan internal gear portion on an inner circumferential surface thereof tobe meshed with the planetary gear section; and a ring gear outer partcoupled to an outer surface of the ring gear inner part, and formed withan external gear portion on an outer circumferential surface thereof tobe meshed with the transmission gear section.
 5. The parking brakeapparatus of claim 4, wherein the ring gear inner part projects moretoward the sun gear section than the ring gear outer part, and surroundsthe sun gear section and the planetary gear section.
 6. The parkingbrake apparatus of claim 1, wherein the gears of the load transmissionunit comprise: a pair of ring gear sections; and at least onetransmission gear section disposed between the pair of ring gearsections, and meshed with the ring gear sections, wherein thetransmission gear section is made of a magnetic material, and whereinthe magnet unit is disposed to face the transmission gear section whichis made of the magnetic material, and the hall sensor unit senses achange in magnetic field according to rotation of the transmission gearsection.
 7. The parking brake apparatus of claim 6, wherein each of thepair of ring gear sections comprises: a ring gear inner part formed withan internal gear portion on an inner circumferential surface thereof tobe meshed with the planetary gear section; and a ring gear outer partcoupled to an outer surface of the ring gear inner part, and formed withan external gear portion on an outer circumferential surface thereof tobe meshed with the transmission gear section.
 8. The parking brakeapparatus of claim 7, wherein the ring gear inner part projects moretoward the sun gear section than the ring gear outer part, and surroundsthe sun gear section and the planetary gear section.
 9. The parkingbrake apparatus of claim 1, wherein each of the pair of pressing unitscomprises: a sun gear section rotated by receiving power from the powertransmission section; a planetary gear section rotated by being meshedwith the sun gear section; a carrier section coupled to the planetarygear section; and a piston section connected to the carrier section, andpressing the brake pad by being moved toward the brake pad throughreceiving rotational power from the planetary gear section.
 10. Theparking brake apparatus of claim 9, wherein the power transmissionsection further includes a transmission worm wheel which is disposed ata middle portion of a transmission shaft, is coupled to the motorsection and receives power from the motor section, and wherein thetransmission worm gears are disposed at both sides of the transmissionworm wheel, and each transmit a rotation force of the transmission wormwheel to the sun gear section.
 11. The parking brake apparatus of claim1, wherein the hall sensor unit is configured to be coupled to an alarmunit and to provide an alarm signal to the alarm unit when the abnormaloperation of the load transmission unit is determined by the hall sensorunit.
 12. A parking brake apparatus for a vehicle, comprising: a motorsection receiving electric power from an outside, and generating power;a power transmission section rotated by driving the motor section, andincluding transmission worm gears; a pair of pressing units receivingpower from the power transmission section and pressing a brake pad; aload transmission unit installed between the pair of pressing units,connected to each of the pair of pressing units, transmitting a pressingload of any one of the pair of pressing units to the other pressingunit, and made of a magnetic material; a magnet unit disposed to bespaced apart from the load transmission unit; and a hall sensor unitdisposed between the load transmission unit and the magnet unit, andsensing a change in magnetic field according to rotation of the loadtransmission unit, wherein the load transmission unit comprises a pairof ring gear sections which are directly meshed with each other, whereineach of the pair of ring gear sections is rotatable by being meshed witha planetary gear section, wherein at least any one of the pair of ringgear sections is made of a magnetic material, and wherein the magnetunit is disposed to face the ring gear section which is made of themagnetic material, and the hall sensor unit senses a change in magneticfield according to rotation of the ring gear section.
 13. A parkingbrake apparatus for a vehicle, comprising: a motor section receivingelectric power from an outside, and generating power; a powertransmission section rotated by driving the motor section, and includingtransmission worm gears; a pair of pressing units receiving power fromthe power transmission section and pressing a brake pad; a loadtransmission unit installed between the pair of pressing units,connected to each of the pair of pressing units, transmitting a pressingload of any one of the pair of pressing units to the other pressingunit, and made of a magnetic material; a magnet unit disposed to bespaced apart from the load transmission unit; and a hall sensor unitdisposed between the load transmission unit and the magnet unit, andsensing a change in magnetic field according to rotation of the loadtransmission unit, wherein the load transmission unit comprises: a pairof ring gear sections; and at least one transmission gear sectiondisposed between the pair of ring gear sections, and meshed with thering gear sections, wherein the transmission gear section is made of amagnetic material, and wherein the magnet unit is disposed to face thetransmission gear section which is made of the magnetic material, andthe hall sensor unit senses a change in magnetic field according torotation of the transmission gear section.
 14. The parking brakeapparatus of claim 13, wherein each of the pair of ring gear sectionscomprises: a ring gear inner part formed with an internal gear portionon an inner circumferential surface thereof to be meshed with theplanetary gear section; and a ring gear outer part coupled to an outersurface of the ring gear inner part, and formed with an external gearportion on an outer circumferential surface thereof to be meshed withthe transmission gear section.
 15. The parking brake apparatus of claim14, wherein the ring gear inner part projects more toward the sun gearsection than the ring gear outer part, and surrounds the sun gearsection and the planetary gear section.